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mountune Focus ST MRX Turbocharger Upgrade
Mountune Focus St Mrx Turbocharger Power Upgrade | Mountune

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Availability: Usually Ships in 1 to 2 Business Days
Product Code: 2363-TU-AA

EFR 6258A Turbo (recommended)
Replace EFR 6258A Turbo with EFR 6758 Turbo
Replace EFR 6258A Turbo with EFR 7163 Turbo [Add $400.00]

Description Installation Guide FAQs

mountune Focus ST MRX Turbocharger Upgrade

The mountune MRX Turbocharger Upgrade for the 2013-18 Focus ST offers greater power output with minimal increase in turbocharger lag, which greatly enhances the driving experience.

Tested and validated over thousands of miles for durability and performance, the mountune MRX Turbocharger Upgrade includes all required hardware, fittings and hoses. This upgrade does not require any fuel system upgrades and is compatible with both 91, 93, and 94 octane fuel. The mountune MRX Focus Turbocharger Upgrade has been developed for those that desire a fully engineered upgrade that provides an optimized power band. Unlike other upgrades that deliver just peak or high RPM power, the mountune MRX Turbocharger Upgrade offers performance throughout the entire power band ensuring a very responsive and drivable car. The MRX Turbocharger Upgrade is designed for those that are looking for well balanced yet extremely powerful performance derived from years of developing race winning Ford 4 cylinder turbocharged engines.

The standard BorgWarner K03 based turbocharger, as found on the Ford EcoBoost engine in the Focus ST, is a capable turbocharger with excellent response and power potential up to the low 300bhp range. For power outputs above that level, a larger turbocharger is required.

The mountune MRX Turbocharger Upgrade is engineered around the BorgWarner EFR turbocharger platform for seamless integration and excellent response and performance. Developed as a complete system with everything available from one source ensures the performance and quality you’ve come to expect from mountune. Because of the unique Low Inertia Gamma-Ti Turbine Wheel, power comes on strong with amazing response and virtually no turbo lag. Integrated recirculation valve ensures smooth drivability and throttle transition. We rely on the BorgWarner EFR 6258A for the foundation of the MRX kit. The EFR 6258A lends itself well to incredible response with virtually no lag while producing incredible power and a very drivable car. For those that wish to go further with slightly higher power levels, the MRX kit is available with the BorgWarner EFR 6758 or EFR 7163 Turbocharger, additional cost may apply.

Power Graph with 6258A Turbocharger

Turbocharger Features:
  • Dual Row Ceramic Ball Bearings - lowest friction and fastest spool/response
  • Water Cooled Center Section
  • Double seals on both turbine and compressor end for extreme durability and resistance to any oil seepage
  • Boost Control Solenoid Valve Integrated to Compressor Housing
  • Integrated Speed Sensor mounting provisions
  • Low Inertia Gamma- Ti Turbine Wheel
  • Stainless Steel Turbine Housing

Kit Features:
  • mountune Ni Resist turbocharger adapter
  • Preformed coolant hard lines ensure trouble free installation and performance
  • Mounting brackets to retain original heat shield
  • 6-ply reinforced silicone primary compressor intake hose assembly - Allows for maximum flow while minimizing false knock caused by metal to metal contact
  • BorgWarner Integrated recirculation valve ensures smooth OE operation and perfect drivability. Optional mountune recirculation valve can be installed

What's included:
1x mountune Ni-resist Cast Turbo Adapter Assembly
1x mountune Ultra Duty T25 Turbine Inlet Gasket
1x BorgWarner EFR-6258A Turbocharger Assembly (BorgWarner EFR-6758 or EFR-7163 optional)
1x mountune Motorsport Downpipe
1x mountune 6-Ply Compressor Inlet Hose Assembly
1x Stainless Steel Hose Clamp – SAE #52
1x Stainless Steel Hose Clamp – SAE #44
1x Turbocharger Oil Inlet Hose Assembly
1x Adapter Fitting, M12x1.5 to -4
1x Crush Washer, M12
1x Adapter Fitting, M14x1.5 to -6
1x Crush Washer, M14
1x Water Pipe #1, Block to Turbo
1x Water Pipe #2, Water Neck to Turbo
1x Tube Adapter, Turbo Oil Drain
1x Gasket, Oil Return Tube
1x mountune 5-Ply Compressor Outlet Silicone Elbow Hose
1x V-Band Clamp, EFR Exhaust Outlet
1.65’ Vacuum Hose, Silicone 4mm
2x Screw, M8 x 1.25 x 16 Socket Head
2x Nut, M6 x 1.0 Flanged Nylon Locknut
1x Stainless Steel Hose Clamp – SAE #32
1x Stainless Steel Hose Clamp – SAE #36
2x Nut, M6 x 1.0 Flanged, Serrated
2x Screw, M6 x 1.0 x 25 Socket Head

What you need:
  • Upgraded intercooler such as mountune PN 2363-IC-MR1
  • Cobb Accessport and a competent tuner.
  • mountune Intake or suitable option PN 2363-CAIS-BA

As with any upgrade of this type, additional strain is placed upon your engine and drive train. While we have thoroughly tested and validated the 6258A upgrade without issues, additional power, cylinder pressure and temperatures may cause engine damage and/or complete failure. It is advised that you upgrade your internal engine components and drive train to support the additional power and performance. For motorsport and track use, it is strongly recommended to upgrade your engine internal components to avoid catastrophic engine failure. Please note the use of the BorgWarner EFR 6758 turbocharger has not been validated by Mountune. This product is for race and track use only.

This part has been designed and is intended for off-highway application only. Installation of this part on a vehicle that is driven on public roads may violate U.S. and Canadian laws and regulations relating to emission requirements and motor vehicle safety standards. Click Here for Emissions compliance information.

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Sale price:$489.00


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Average Rating: Average Rating: 5 of 5 5 of 5 Total Reviews: 5 Write a review »

  1 of 1 people found the following review helpful:
5 of 5 Awesome August 5, 2017
Reviewer: Thomas Rossland from Drammen, Buskerud Norway  
As sold, a perfect match for the 2.0 ecoboost engine.

I have done 30.000 km with this turbo without any issues now. Really pushes good during trackdays and road driving.

Tips: Camshafts make a huge difference on this kit, and make sure you have all the parts before install

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  0 of 1 people found the following review helpful:
5 of 5 Street and Track November 20, 2016
Reviewer: Kenneth Kiesow from Monroe, WA United States  
Having now a big turbo and everything required to make it worthwhile on this car, for a conservatively engineered package it's brilliant.  My installing dealer made a special note to say how precise the fit was on all of the parts.  Power is a given; if you haven't invested in suspension and drivetrain, don't start here.

Power band is, as others have noted, broad and controllable.  This *must* be paired with the quaife differential or you're wasting your time.

Do all this however, and you cannot help but express extra adrenaline whenever the opportunity presents :-)

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  0 of 0 people found the following review helpful:
5 of 5 Excellent drivability and glorious power! September 29, 2016
Reviewer: Adam from Plano, TX United States  
I did a lot of research before buying a turbo kit, and this was exactly what I was looking for.  I bought the catted downpipe that mates up to the turbo along with this kit, and that was all I needed to get going ( I already had a Cobb AccessPort). No need to worry about sourcing an external BOV and where to place it, as a BorgWarner BPV comes with the turbo.

Randy worked with me on the tuning and the end result is a car that responds almost like it did on the stock turbo: instant boost, no turbo lag, except with a  ton more power! The car is very responsive and incredibly fun to drive on the street, with instant boost and power available form traffic light to traffic light.

If maximum peak power up high in the rpm range is not your end goal, but rather a super responsive car with next to no turbo lag and a large area under the power curve, this is the kit you need to buy.

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  1 of 1 people found the following review helpful:
5 of 5 Big Turbo Power! April 5, 2016
Reviewer: Chris Cata from Omaha, NE United States  
I purchased the MRX kit right when it became available.  Installation went well and overall the experience with the EFR Turbo (6258) has been great.  The car pulls wonderfully all the way to redline.  Currently seeing vDyno numbers right in line with what Mountune posted - ~350hp/350tq.

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  3 of 3 people found the following review helpful:
5 of 5 MRX February 7, 2016
Reviewer: Robert Draheim from California, MD United States  

My review and pictures can be found here:


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